The invention concerns a transfer car in a conveyance system for metal coils with a chassis that can be moved along a conveyance path by means of a drive and with means for raising and lowering a support saddle along a linear vertical guide on a base frame.
So-called coil transfer cars are used for transporting metal coils in and out, e.g., in strip treatment installations. One well-known design has, for example, a central guide for the support saddle and two hydraulic cylinders for operating the lifting unit.
The guide for the lifting unit can be designed both as a circular guide and as a rectangular guide and generally moves in a guide slot provided for it in the foundation. This slot must be very deep in some cases and requires a reliable cover, possibly with covering elements also carried by the coil transfer car, to prevent accidents.
Another well-known design uses a so-called scissor lifting table for guiding the support saddle and actuating the lifting movement. In this system, the lifting cylinders necessary for lifting act on the scissor system. These coil cars can be built relatively flat, and the opening necessary in the foundation can be correspondingly smaller. However, the unfavorable application of force of the hydraulic cylinders on the scissor system and the nonlinear lifting movement must be seen as disadvantages.
Another well-known variant of these coil transfer cars has a lifting system arranged eccentrically next to the useful load. The advantage of this system lies in the very flat type of construction and in the elimination of the foundation pit. However, the unfavorable application of force and the limited accessibility of the useful load are disadvantages.
The document EP 0 569 719 A1 describes a coil transport system with air cushion vehicles for straight ahead travel and travel around bends, in which the air cushion vehicle has on its longitudinal sides mechanical lateral guides, which can be alternately actuated on the right-hand and left-hand sides, to which guideways are assigned, and these lateral guides allow transverse movement.
The document EP 0 061 557 A2 describes a conveyor for sheet-metal coils, which has a coil car that can be moved along the path of travel by means of a drive. To ensure exact position determination of the coil car on the path of travel, the drive for the coil car consists of a rack that extends along the path of travel and meshes with a drivable gear of the coil car, and the rack serves as an incremental scale for a length-measuring device, which comprises a unit for scanning the incremental scale and at least one counter for counting the output pulses of the scanning unit.